The present invention relates to a process for treating hair; and to a composition for use in such treatment. It is particularly applicable to the styling of human hair, e.g. by `permanent waving`.
It has long been known that hair consists largely of protein (`keratin`) and that its physical form is affected by the arrangement of disulphide linkages between cysteine residues. Thus known hair treatment compositions employ thiols which are believed to undergo redox reactions so that the keratin disulphide linkages are unmade and remade, allowing the hair to be given a new configuration during the process. However, the thiols are disagreeable, even dangerous, compounds and the compositions generally need to be strongly alkaline. They are unpleasant to use, and can harm the skin and hair.